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Difference in expansion and dehydration behaviors between NH$$_4$$- and K-montmorillonite

川喜田 竜平; 齋藤 彬人*; 佐久間 博*; 安楽 総太郎; 菊池 亮佑*; 大竹 翼*; 佐藤 努*

Applied Clay Science, 231, p.106722_1 - 106722_7, 2023/01

 被引用回数:1 パーセンタイル:30.27(Chemistry, Physical)

Montmorillonite (Mt) expansion and swelling are key factors for barrier performance of bentonite in trans-uranic (TRU) and high-level radioactive waste disposals. In the case of co-located geological disposal of TRU waste with high level waste, ammonium ion (NH$$_4$$$$^+$$) which is changed from nitrate ion leached from TRU waste has possibility to contact with bentonite, exchange interlayer cation of Mt to form NH$$_4$$-Mt, and deteriorate its performance. Because of similar hydration energy of NH$$_4$$$$^+$$ to K$$^+$$, NH$$_4$$-Mt could have lower expandability or change to non-expandable mineral as reported on K-Mt. Therefore, expansion and alteration behaviors of NH$$_4$$-Mt, especially comparison to the behaviors of K-Mt, are necessary to understand for safety assessment of the waste disposal. In this study, the hydration behavior of NH$$_4$$-Mt was investigated by XRD and molecular dynamics (MD) simulation in comparison with K-Mt. XRD profiles under Relative Humidity (RH) control showed that expansion of NH$$_4$$-Mt was similar to that of K-Mt at more than RH40% with slightly different d-values. However, expansion of NH$$_4$$-Mt kept at lower than RH20%, while K-Mt easily dehydrate at the same RH. MD simulation revealed that hydrogen bonding (HB) in NH$$_4$$$$^+$$ molecules causes the difference in hydration behavior between NH$$_4$$- and K-Mt, as HB cause larger basal spacing at dehydrated state and easier hydration. This gap on hydration may attribute the difference in alteration to non-expandable minerals after dehydration, indicating that NH$$_4$$$$^+$$ have lower possibility for alternation and smaller effect on barrier performance of bentonite than K$$^+$$.


Rotation of complex ions with ninefold hydrogen coordination studied by quasielastic neutron scattering and first-principles molecular dynamics calculations

大政 義典*; 高木 茂幸*; 戸嶋 健人*; 横山 凱乙*; 遠藤 亘*; 折茂 慎一*; 齋藤 寛之*; 山田 武*; 川北 至信; 池田 一貴*; et al.

Physical Review Research (Internet), 4(3), p.033215_1 - 033215_9, 2022/09

Quasielastic neutron scattering (QENS) and neutron powder diffraction of the complex transition metalhydrides Li$$_5$$MoH$$_{11}$$ and Li$$_6$$NbH$$_{11}$$ were measured in a temperature range of 10-300 K to study their structures and dynamics, especially the dynamics of the hydrogen atoms. These hydrides contain unusual ninefold H coordinated complex ions (MoH$$_9^{3-}$$ or NbH$$_9^{4-}$$) and hydride ions (H$$^-$$). A QENS signal appeared $$>$$ 150 K due to the relaxation of H atoms. The intermediate scattering functions derived from the QENS spectra are well fitted by a stretched exponential function called the Kohlrausch-Williams-Watts functions with a small stretching exponent $$beta approx$$ 0.3-0.4, suggesting a wide relaxation time distribution. The $$Q$$ dependence of the elastic incoherent structure factor is reproduced by the rotational diffusion of MH$$_9$$ (M = Mo or Nb) anions. The results are well supported by a van Hove analysis for the motion of H atoms obtained using first-principles molecular dynamics calculations. We conclude that the wide relaxation time distribution of the MH$$_9$$ rotation is due to the positional disorder of the surrounding Li ions and a unique rotation with MH$$_9$$ anion deformation (pseudorotation).


Evaluation of sample cell materials for aqueous solutions used in quasi-elastic neutron scattering measurements

富永 大輝*; 佐原 雅恵*; 川北 至信; 中川 洋; 山田 武*

Journal of Applied Crystallography, 54(6), p.1631 - 1640, 2021/12

 被引用回数:3 パーセンタイル:50.25(Chemistry, Multidisciplinary)

For quasi-elastic neutron scattering (QENS) studies, sample cells made of pure or alloyed aluminum are frequently employed. Although the Al surface is protected by a passivating film, this film is not robust. Therefore, when the sample is an aqueous solution, chemical interactions between the Al surface and sample, promoted by corrosive entities such as chloride ions and certain conditions of pH, can compromise the integrity of the cell and interfere with the experiment. In this study, the corrosion susceptibilities of Al and its alloys were investigated by subjecting them to various treatments; the results were compared with those of other candidate materials with low chemical reactivity. This work showed that alloys with higher Al content and boehmite-coated surfaces are resistant to corrosion. In particular, for Al, the resistance is due to a reduction in the contact area achieved by reducing the surface roughness. QENS measurements of empty sample cells made of these materials revealed two results: (1) the profile of the cell fabricated with a copper-free Al alloy showed a minor dependence on the scattering vector magnitude $$Q$$ and (2) reducing the real surface area of Al effectively suppresses its scattering intensity, while boehmite coating strengthens the scattering. Cells fabricated with Mo, Nb and single-crystal sapphire can be used as alternatives to Al because of their low scattering intensity and reduced dependence on $$Q$$.


Conformational dynamics of a multidomain protein by neutron scattering and computational analysis

中川 洋; 齋尾 智英*; 長尾 道弘*; 井上 倫太郎*; 杉山 正明*; 味戸 聡志; 富永 大輝*; 川北 至信

Biophysical Journal, 120(16), p.3341 - 3354, 2021/08

 被引用回数:1 パーセンタイル:10.02(Biophysics)



Corrosion of aluminum-based containers for neutron studies with aqueous samples under low temperatures

富永 大輝*; 佐原 雅恵*; 川北 至信; 中川 洋; 島本 直伸*

JPS Conference Proceedings (Internet), 33, p.011094_1 - 011094_5, 2021/03




Position dependency of the scattered intensity in the time-of-flight backscattering spectrometer DNA

松浦 直人*; 山田 武*; 富永 大輝*; 小林 誠*; 中川 洋; 川北 至信

JPS Conference Proceedings (Internet), 33, p.011068_1 - 011068_6, 2021/03



Quartz cell for a backscattering spectrometer

富永 大輝*; 川北 至信; 中川 洋; 山田 武*; 柴田 薫

JPS Conference Proceedings (Internet), 33, p.011086_1 - 011086_5, 2021/03


後方散乱型中性子分光器、特にJ-PARC MLFのBL02(DNA)分光器用に最適化された二重円筒型石英試料セルを開発した。一端を閉じられた石英ガラス管を0.55mmの厚みまで削り、内筒を底部の突起によって外筒に同芯になるように挿入する。この石英セルは、標準的に用いられているアルミセルの表面に触れさせたくない試料に用いられる。石英セルと標準アルミセルの容器散乱の効果を重水バッファ試料を使って中性子準弾性散乱実験(QENS)により確かめた。Qが1[1/A]未満の領域では石英セルとアルミ容器の弾性散乱プロファイルはほぼ同一であった。一方Qが1[1/A]以上の領域では、石英ガラスのFSDPのために、プロファイルが異なることが分かった。この領域では、吸収補正や石英セルの個々の厚みの差を考慮した解析が必要である。


Dynamics of proteins with different molecular structures under solution condition

井上 倫太郎*; 小田 隆*; 中川 洋; 富永 大輝*; 齋尾 智英*; 川北 至信; 清水 将裕*; 奥田 綾*; 守島 健*; 佐藤 信浩*; et al.

Scientific Reports (Internet), 10, p.21678_1 - 21678_10, 2020/12

 被引用回数:3 パーセンタイル:15.31(Multidisciplinary Sciences)



Continuum excitation and pseudospin wave in quantum spin-liquid and quadrupole ordered states of Tb$$_{2+x}$$Ti$$_{2-x}$$O$$_{7+y}$$

門脇 広明*; 脇田 美香*; F${aa}$k, B.*; Ollivier, J.*; 河村 聖子; 中島 健次; 高津 浩*; 玉井 元健*

Journal of the Physical Society of Japan, 87(6), p.064704_1 - 064704_6, 2018/06

 被引用回数:9 パーセンタイル:58.67(Physics, Multidisciplinary)

フラストレートしたパイロクロア酸化物Tb$$_{2+x}$$Ti$$_{2-x}$$O$$_{7+y}$$についての非弾性中性子散乱実験を行った。相転移を示さず量子スピン液体になる系($$x = -0.007 < x_{c} < sim -0.0025$$)と、二つの四重極秩序を起こす系($$x = 0.000, 0.003$$)の単結晶試料を調べた。量子スピン液体の系は弾性散乱の他に0.1meV程度の連続励起を持ち、$$x$$が増加すると連続励起領域から四重極のスピン波が分かれてくる。これは、粉末試料の結果と同じであり、試料の$$x$$の制御がよくできている証拠である。


次世代中性子生物学; J-PARCワークショップ「次世代中性子生物学」の報告; 2017年3月22日$$sim$$23日,いばらき量子ビーム研究センター

杉山 正明*; 中川 洋; 井上 倫太郎*; 川北 至信

JAEA-Review 2017-024, 40 Pages, 2017/12


現在、我が国ではJ-PARC・JRR-3等の高強度高品質の中性子源が整備され中性子線を用いた生命科学研究の推進が強く望まれている。そこで、我が国中性子生物学の発展に寄与することを目指して2017年3月22日$$sim$$23日国際Workshop「Neutron biology for next generation」がJ-PARCワークショップとして開催された。このWorkshopには日本国内の中性子分光器の装置研究者及び中性子散乱を精力的に利用している国内外の生命科学者が集まり、上記テーマについて装置・実験手法、最新の研究成果及びその動向について多方面より議論した。本レポートはオーガナイザーによるWorkshopの報告である。


Inelastic and quasi-elastic neutron scattering spectrometers in J-PARC

瀬戸 秀紀; 伊藤 晋一; 横尾 哲也*; 遠藤 仁*; 中島 健次; 柴田 薫; 梶本 亮一; 河村 聖子; 中村 充孝; 川北 至信; et al.

Biochimica et Biophysica Acta; General Subjects, 1861(1), p.3651 - 3660, 2017/01

 被引用回数:29 パーセンタイル:80.32(Biochemistry & Molecular Biology)



Repetition Rate Multiplication: RRM, an advanced measuring method planed for the backscattering instrument, ${it DNA}$ at the MLF, J-PARC

高橋 伸明; 柴田 薫; 川北 至信; 中島 健次; 稲村 泰弘; 中谷 健; 中川 洋; 藤原 悟; 佐藤 卓*; 筑紫 格*; et al.

Journal of the Physical Society of Japan, 80(Suppl.B), p.SB007_1 - SB007_4, 2011/12

 被引用回数:6 パーセンタイル:43.71(Physics, Multidisciplinary)

A TOF-BSS named ${it DNA}$ has been under construction on BL02 in the MLF of J-PARC. We have estimated expected performances of several candidates under realistic neutron source parameters at MLF. The expected neutron intensity under comparable energy resolutions of the ${it DNA}$-type is 2.6 times higher than that of the BASIS-type. Consequently, we have chosen the CM with pulse-shaping device for ${it DNA}$. Pulse-shaping is a good technique from a view point of a variability of resolution. On the other hand, a neutron energy band passing through the pulse-shaping chopper is limited and thus scanning range with one phase of the chopper is narrow. Of course, ${it DNA}$ also can access larger energy transfers by appropriate phasing of the pulse-shaping chopper. In addition, ${it DNA}$ will be able to utilize Repetition Rate Multiplication (RRM). RRM is essentially a way to employ multiple pulse-shaped incident neutron beams to effectively increase neutron counting time to more efficiently measure the inelastic region. In this presentation we will show the chopper sequence and introduce the RRM mode of the forthcoming backscattering spectrometer ${it DNA}$ in detail.


First flight demonstration of film-laminated InGaP/GaAs and CIGS thin-film solar cells by JAXA's small satellite in LEO

森岡 千晴*; 島崎 一紀*; 川北 史朗*; 今泉 充*; 山口 洋司*; 高本 達也*; 佐藤 真一郎; 大島 武; 中村 揚介*; 平子 敬一*; et al.

Progress in Photovoltaics; Research and Applications, 19(7), p.825 - 833, 2011/11

 被引用回数:21 パーセンタイル:67.54(Energy & Fuels)

The electrical performances of InGaP/GaAs dual-junction solar cells and CIGS solar cells in space have been demonstrated by JAXA's small satellite which flew in a low-earth orbit since January 2009. This flight demonstration is the first experiment for a thin-film III-V multi-junction solar cell in the world. Thin-film solar cells were laminated using transparent polymer film in place of conventional coverglass for protection of solar cell's surface. The film-laminated cells were observed for short-circuit current degradation. The ground tests indicated that the cause of the degradation was attributed to the film coloring by obliquely incident UV rays, not to space radiations (protons and electrons). This is because the lamination film has UV-reflective multilayer coating on its surface. The flight data and the predicted results were in reasonable agreement with each other. Thus, we could verify the validity of the ground tests and prediction methodology for film-laminated solar cell in this study.



柴田 薫; 高橋 伸明; 中川 洋; 藤原 悟; 片岡 幹雄; 佐藤 卓*; 川北 至信*; 筑紫 格*

日本結晶学会誌, 50(1), p.46 - 50, 2008/02



Variation in groundwater levels, pore pressures and crustal strain related to earthquakes in the upper granite and sedimentary formations in the area of western Tono, Japan

吾妻 瞬一*; 石井 紘*; 浅井 康広*; 北川 有一*; 脇田 宏*; 山内 常生*; 浅森 浩一

Geodynamics of Atotsugawa Fault System, p.173 - 179, 2007/00



Remote monitoring of airborne asbestos particles using laser-induced fluorescence imaging

大図 章; 江坂 文孝; 川北 裕司*; 岡本 隆太*; 今城 勝治*; 小林 喬郎*

Reviewed and Revised Papers Presented at the 23rd International Laser Radar Conference (ILRC-23), p.107 - 108, 2006/07



Si substrate suitable for radiation-resistant space solar cells

松浦 秀治*; 岩田 裕史*; 鏡原 聡*; 石原 諒平*; 米田 雅彦*; 今井 秀彰*; 菊田 真経*; 井上 裕喜*; 久松 正*; 川北 史朗*; et al.

Japanese Journal of Applied Physics, Part 1, 45(4A), p.2648 - 2655, 2006/04

 被引用回数:15 パーセンタイル:49.51(Physics, Applied)

宇宙用Si太陽電池の耐放射線性強化に関する研究の一環として、1MeV電子線又は10MeV陽子線照射がSi基板中の正孔濃度に及ぼす影響をホール効果により調べた。試料は、ボロン(B), アルミニウム(Al), ガリウム(Ga)等の異なる種類のアクセプタを添加したCZ成長Si基板,MCZ法で作製したB添加Si基板及びFZ法で作製したB添加Si基板を用いた。その結果、CZ基板では、陽子線照射量の増加とともに正孔濃度が減少し、添加不純物によらず2.5$$times$$10$$^{14}$$/cm$$^{2}$$で伝導キャリアのタイプが正孔から電子へと変化した。また、B添加したCZ, MCZ, FZ基板を比較したところ、いずれの基板も電子線照射量の増加とともに正孔濃度は減少するが、その減少の大きさはCZ, MCZ, FZの順であり、1$$times$$10$$^{17}$$/cm$$^{2}$$照射でCZ基板のキャリアタイプが電子に変化したのに対してMCZ, FZは正孔のままであった。CZ基板では添加不純物によらず正孔濃度の減少は同程度であること、CZ, MCZ, FZの順で正孔濃度の減少が少ないこと、CZ, MCZ, FZの順で基板に残留する酸素原子が少なくなることを考慮すると、正孔濃度を減少させる照射誘起欠陥の構造は、添加不純物と空孔の複合欠陥ではなく、基板に残留する酸素原子と空孔型の複合欠陥であることが示唆される。


イメージング遠隔パーティクルカウンター; 後方散乱光を利用する新しい浮遊微粒子の遠隔計測システム

大図 章; 岡本 隆太*; 川北 裕司*

クリーンテクノロジー, 16(3), p.56 - 61, 2006/03



Change of majority-carrier concentration in p-type silicon by 10 MeV proton irradiation

岩田 裕史*; 鏡原 聡*; 松浦 秀治*; 川北 史朗*; 大島 武; 神谷 富裕

Proceedings of the 6th International Workshop on Radiation Effects on Semiconductor Devices for Space Application (RASEDA-6), p.143 - 146, 2004/10




鈴木 正年; 羽沢 知也; 石崎 洋一*; 小原 道士*; 稲田 勝利*; 米川 光則*; 脇田 広志*

JAERI-Tech 2004-060, 153 Pages, 2004/09



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